Concrete curb laying machine

ABSTRACT

A machine for handling, conveying, compacting and distributing formable material such as concrete upon or along a work location in the desired grade, slope and directional configuration defined by an external reference extending along the path of travel. In one embodiment the machine includes a concrete receiving hopper on one side and a conveyor which elevates the concrete across the machine into a compaction hopper on the other side for gravity feeding to a working tool, such as a mule shoe. The receiving hopper is located on one side and pivotal of the machine and the compaction hopper and working tool are on the other side, with the conveyor in between; an arrangement found to supplement the leveling, traction and steering capabilities of wheels and tractor supported vehicles. The longitudinal side location of the working tool such as a slip-form, in cooperation with the independent front and rear steering of the pairs of ground engagement means maintains the tool in tangential relationship to outside curves and in chordal relationship to inside curves, undisturbed by gradual or abrupt changes in the load of onboard material and irrespective of grade deviations of considerable magnitude.

Unite States atent 1 1 1111 3,749,505 Miller et a1. July 31, 1973 15 CONCRETE CURB LAYING MACHINE 3,595,144 11/1971 Rink 94/46 R Filed:

lnventors: Charles P. Miller; Allen R. Miller,

Assignee: Miller Formless Co., Inc., Mcl'lenry,

Sept. 17, 1971 Related US. Application Data Continuation-impart of Ser. No. 774,014, Nov. 7,

1968, Pat. No. 3,606,827.

[52] US. Cl. 404/98 [51] Int. Cl. E01c ll/28 [58] Field of Search 94146 R, 46 AC, 44; 404/98 [56] References Cited UNITED STATES PATENTS 2,128,273 8/1938 Stevens 94/46 AC 2,649,185 8/1953 Lichtenberg... 94/46 R X 3,016,809 l/1962 McNeill 94/46 R 3,053,156 9/1962 Jennings 94/46 R 3,158,945 12/1964 Curlett 94/46 AC 3,249,026 5/1966 Curlett 94/46 AC 3,161,117 12/1964 Supject 94/46 R 3,188,928 6/1965 Guntert... 94/46 R 3,292,511 12/1966 Cheney 94/46 AC 3,362,308 1/1968 Austin 94/46 R 3,540,359 11/1970 Swisher 94/46 R Primary E, r 1rninerNile Byers, Jr. Attorney-Watson D. l-larbaugh and Bruce K. Thomas [57] ABSTRACT A machine for handling, conveying, compacting and distributing formable material such as concrete upon or along a work location in the desired grade, slope and directional configuration defined by an external reference extending along the path of travel. In one embodiment the machine includes a concrete receiving hopper on one side and a conveyor which elevates the concrete across the machine into a compaction hopper on the other side for gravity feeding to a working tool, such as a mule shoe. The receiving hopper is located on one side and pivotal of the machine and the compaction hopper and working tool are on the other side, with the conveyor in between; an arrangement found to supplement the leveling, traction and steering capabilities of wheels and tractor supported vehicles. The longitudinal side location of the working tool such as a slip-form, in cooperation with the independent front and rear steering of the pairs of ground engagement means maintains the tool in tangential relationship to outside curves and in chordal relationship to inside curves, undisturbed by gradual or abrupt changes in the load of onboard material and irrespective of grade deviations of considerable magnitude.

3 Claims, 6 Drawing Figures PATENTEU m3 1 197a SHEET 1 OF 3 lNl/E/VTORS: CHARLES R M/L ALLEN R M/LLER DAV/D J. M/LLER By WYJLMM Arrorneys PATENIEU JUL 3 1 1973 SHEET 2 BF 3 //v|//v TORS: CHARLES ,9 MM ALLEN R. MILLER 04 W0 .1. M/LLER A rrorneys PMENIHJ M Q SHEET 3 BF 3 lNVEfi/TO/PS. CHARLES E M/LLE f? ALLEN R. M/LLE/P DAV/D J. MILLER Attorneys CONCRETE CURB LAYING MACHINE RELATED APPLICATIONS This application is a continuation-impart of application Ser. No. 774,014, filed Nov. 7, 1968 by the instant inventors now US. Pat. No. 3,606,827, and the disclosure therein is incorporated by reference.

BACKGROUND OF THE INVENTION As set forth in part in said parent application, the older methods of road building employing individual motor scrapers, motor graders, rolling and compacting equipment have now been replaced by automatic machinery capable of simultaneously performing a number of functions. Although, automatically controlled equipment is now capable of speeding up the road building process and also for providing closer tolerances both transversely and longitudinally of the tinished work, there are still serious problems with these machines and also with smaller machines.

To illustrate, road building machines generally comprise a frame to hold the working tool, which may be adjustable in relation to the frame, with a plurality of ground engaging means (wheels or tractors) to provide four corner support and transportation of the machine. The frame and tractors straddle the working tool which is located to do work upon one or more lanes of pavement. The ground engaging means can be a pair of wheels, with or without heavy treaded tires, or two to four endless track units, with power means to drive the units. Steering by means of a pair of tractors is accomplished by crabbing, that is, applying power to one tractor at a time with inherent loss of the control of grade, slope and steering conformity because the pivot or turning point of the machine is transient due to a number of factors, such as, loss of traction of the driven tractor and digging into soft terrain, etc. With four tractors on large paving machines close tolerance steering potential is unnecessary. The frames of such road building machines are huge and being adapted to span one or more lanes of concrete roadway, depend more upon their mass and size (length) than the suspension to accomplish leveling. Steering though is inexact and the machines do not follow the grade line smoothly. Machines which are used for curb, median and gutter work, as presently in use, are smaller, have a pair of ground engaging means, and straddle the working tool. Such machines lack versatility and the capability of negotating uneven grade or forming accurate curves.

Any advantage that is gained in using only a pair of ground engagement means, that is, a single tractor on each side of the main frame, for compactness and as much maneuverability as crabbing will impart, is lost in limitations on the on-board capacity for concrete, particularly because the mule shoe is straddle-mounted and fed directly with concrete so that a low silhouette is necessary. Machines of this nature have little or no on-board capacity and can only lay curbing while concrete is supplied by a truck. There is no control of the consistency, mixing or aeration of the concrete as it comes from the ready-mix truck. The speed of operation is reduced, and the consistency of the concrete used becomes critical to the quality of the finished curb or median because thorough compaction and mixing are not provided.

As a consequence prior art curb and sidewalk machines run on tracks, which are the form for the concrete being laid, are adapted to lay curbings and dividers on previously laid asphalt or concrete areas or require a carefully prepared grade on which to operate, which grade must be at least as wide as the machine. Also, because of the two tractor systems, with four ram supports connected to the frame, attempts are made to compensate for the lack of steering, leveling and propulsion capability by using stiff metal bands as the grade reference and adjustably mounting the working tool between the tractors with means to maintain the trailing edge of the tool a fixed distance from the grade reference.

The instant invention has as its objective the elimination of these and other disadvantages of the prior art machines by providing the combination of a side mounted tool which can lay curbing or the like adjacent to earth banks, trees, buildings, pavement lanes, etc. along a narrow grade path while the machine traverses a relatively rough grade or operates from an elevation above the grade or a depression below the grade. Other advantages and features of the invention will be described or become apparent as the description proceeds.

SUMMARY OF THE INVENTION The present invention concerns, in one embodiment, the provision of a capacitous on-board formable material handling system supported by the frame and connected to and supplying the side mounted tool in such a manner that rapid and continuous operation is made practical and the quality and accuracy of the end product being formed along a grade is enhanced. In another embodiment the working tool is oriented longitudinally along the side of the main frame so that its mid-portion is substantially central of the longitudinally spaced suspension points of a pair of independently steerable ground engagement means or tractors on that side or substantially central of a longitudinally spaced pair of independently steerable ground engagement means which are connected to the ends of a walking beam having a single central suspension point connected to the frame.

More particularly a construction machine is provided with the foregoing material handling system and also having a main frame, a pair of independent suspension members, such as dual acting rams, on one side of the frame. The rams are connected to and adjustably support the frame on a pair of front and rear ground engagement means on one side, and a single suspension member, such as a dual acting ram, is used on the other side or the frame, pivotally connected to and adjustably supporting the frame substantially central of a walking beam which has a pair of front and rear ground engagement means, one at each end. The four ground engagement means are adapted to transport the machine over rough grade and together they form a self-propelled support for the frame. The front and rear ground engagement means on the one side of the frame are each rotatably mounted on a vertical axis from the suspension member and the front and rear ground engagement means on the other side of the frame are each rotatably mounted on a vertical axis from the ends of the walking beam. The front and rear pairs of ground engagement means on opposite sides of the frame are linked together transverse of the frame so as to be steerable in unison but independently, so that the front pair can be turned in either direction, independent of the rear pair which can be turned in either direction. With front and rear steering each pair need only turn about 15 in either direction. The suspension points or rams on the one side of the frame are independently controlled by sensor means running along the grade reference to control the grade or level of the frame and tool, fore and aft, along the path of travel and the single suspension point is independently controlled by a pendulum means or the like to maintain the desired slope or level across the frame and tool as the machine progresses. Propulsion means are provided to drive the pair of ground engagement means on one side in unison and to drive the pair of ground engagement means on the other side in unison. Preferably, the ground engagement means are tractors having endless treads. Although the invention will be described in relation to an automatic curb-forming machine it will become apparent that the invention can be applied to any type of materiahhandling machine.

DESCRIPTION OF THE DRAWINGS The invention is illustrated by the drawings wherein:

FIG. 1 is a perspective view showing the front and outboard or curb side of the machine of this invention showing the material handling system in operation;

FIG. 2 is a side elevational view of the machine illustrated in FIG. 1 showing the outboard or curb side;

FIG. 3 is an end elevational view partly in crosssection taken along the lines 33 of FIG. 2',

FIG. 4 is a side elevational view taken along the lines 44 of FIG. 3 to show the inboard side of the machine and the relation of the receiving hopper to the screw conveyor and front of the machine;

FIG. 5 is a front diagrammatic view of the machine showing the transverse relationship of the tractors to the load of the concrete conveying system; and

FIG.6 is a top or plan view in diagrammatic form showing the relationship of the tractors, the concrete conveying system and the slip-form to illustrate the centers of respective movement of the machine and the working tool in negotiating a curve.

THE PREFERRED EMBODIMENT The following description of the drawings is taken in part from said parent application to include the common subject matter of the disclosure of the instant invention therein supplemented with additional disclosure relating to the present invention, and omitting the description of some of the parts and their functions not herein involved.

Referring to the drawings, particularly FIGS. 1, 2, 3 and 4 this invention is illustrated by the curb-forming machine having the supply or receiving hopper 12 adapted to receive concrete 14 from the chute 16 of a concrete truck (not shown), convey the concrete upwardly through the screw conveyor 18, operated by the hydraulic motor 20 and discharge the concrete from the opening 22 into the feed hopper 24. The concrete is subjected to vibration to eliminate air bubbles in the feed-hopper 24 by means of the electric vibrator 26 run by the motor 28.

Although individual parts comprising the concrete handling system are generally known in the art, their orientation and placement on the machine in the manner shown in conjunction with the side-mounted slipform, is unique, when related to the geometry of the 1 suspension and the changing load as the work is performed. In this instance, the feed hopper 24 has sufficient height and capacity provided by the side walls 25 to provide a gravity compaction zone for the concrete and has an open bottom communicating with the slipform or mule shoe 30. This tool is elongated and affixed to the box frame member 32 (FIG. 3) by means of the adjustable vertical support members 33 and 34 in the rear and 36 and 38 (FIG. 1) in the front. The support members have suitable spaced holes 40 through which bolts are attached to hold the slip-form at desired heights to the box frame member front and rear. The support members also serve to hold the feed hopper 24 as desired. Any arrangement to hold the material handling system to the box frame 32 and provide adjustability of the parts can be used. Thus, the elevation and length of the screw conveyor 18 can also be made adjustable to suit the size, capacity and configuration of the machine. The minimum length of a slip-form used for curbing work is about 3 feet and the maximum length is about 10 feet.

As set forth in said parent application, the slip-form 30 is closed as the front end by the wall member 42 through which extend the tubes 44 having flared open ends to receive the reinforcing rods 46. The tubes 44 are spaced laterally from each other and also spaced above the bottom of the slip-form. Any number of tubes 44 can be used with any desired spaced configuration. The longitudinal side brace 48 ties the slip-form 30 to supports along the bottom edge. The rear end of the slip-form 30 is open and the arrangement is so spaced above the grade level 50 (FIG. 2) to form or lay a continuous curb 52 containing the reinforcing rods 46 as the machine moves in the direction of the arrow 54. The slip form is contoured at the top 56 (FIG. 3) to lay any curb and gutter design to specifications including the so-called battered form illustrated and the other types, namely: drive over, roll and vertical or the Jersey form of divider. The capacities of both the hoppers 12 and 24 are such that the machine can move continuously along the grade 50 and lay a continuous curbing with only intermittent interruptions for the laying of expansion joints as may be required or adjustment of the concrete trucks, which move along with the machine as they discharge their load through the chutes as illustrated by the chute 16. The reinforcing rods 46 are placed in the tubes 44 by hand as the curbing progresses.

The machine is self-contained with the prime mover 60 supplying the power necessary to drive the hydraulic pumps and generators that are required. All functions of the machine can be controlled by one man from the platform 62 from which position the rate of discharge from the hopper 24 can be observed with the control console 63 in convenient access therewith. The top panel 64 of the console contains the controls and instruments for the prime mover 60 and the motive system, while the lower panel 65 contains the controls and instruments forthe electro-hydraulic system. The water tank 66 supplies water as needed to clean off excess concrete on the parts so that it will not harden during idle periods of the machine. In accordance with an embodiment of this invention, spray jets 67 (FIGS. 5 and 6) are provided to convey water at an angle transversely into the conveyor 18 in order to adjust the consistency as the work progresses. The fuel tank is illustrated at 67 (FIG. 3).

Basically, the machine of this invention is a hydraulic-powered self-steering and self-leveling curb-laying device wherein the motion, direction and grade are maintained by automatic or manual control and adjustment, and the concrete is supplied to the slip-form automatically and in continuous, compacted condition as same is carried along and accurately parallel to or in a fixed tangential or chordal distance from a grade reference. The mechanical components to accomplish these are separately described in part as they relate to this invention.

The box frame 32 carries the forward outboard hydraulic cylinder housing 70 in a vertical position at one corner and the rearward outboard hydraulic cylinder housing 72 in a vertical position at the other corner, as two spaced individual suspension points for the slipform or outboard side of the machine for grade control. Affixed to an intermediate position on the inboard side of the box frame 32 is a pair of hydraulic cylinder housings 74 and 70. The cylinders are connected by means of hydraulic hoses to a source of hydraulic power to be described. Thus, the cylinder 70 has the pair of hoses 78 and 79; the cylinder 72 has the pair of hoses 80 and 81; the cylinder 74 has the pair of hoses 82 and 83 and the cylinder 76 has the pair of hoses 84 and 85. The flow of hydraulic fluid therein is reversible and controlled by a valve system to be described. The cylinder housings 74 and 76 are set in side-by-side transverse relationship in FIG. 1, but may also be in fore and aft relationship on the inboard side as shown in FIG. 6.

The cylinders 70, 72, 74 and 76 are affixed to the frame 32 and receive the respective internal cylinders 87, 88, 90 and 92 in telescoping guided relationship to provide straight line vertical adjustment. Within each of these telescoping supports is the double-acting operating cylinder or ram therefor which is connected so as to prevent lateral strain on the assembly as disclosed in the parent application. The telescoping cylinders 87, 88, 90 and 92 and their internal rams become in efiect directly acting adjustable support means for the frame.

The rams operating in the telescoping cylinders 74 and 76 on the outboard side of the machine and their respective bases 104 are affixed to the bogey mountings 116, forming the front and rear individual suspension units for the front and rear crawler type tractor units 120 on that side of the machine.

On the inboard side (see FIG. 4), the pair of rams within the telescoping members 90 and 92 are mounted in side by side position from a rectangular base 122 of the saddle 123 (FIG. 2) which is pivotally mounted intermediate the ends of the walking beam 124 by means of the angle braces 126, on each side, and the pivot pin 128, which extends through the saddle and the beam, forming a central bogey mount. Also on the inboard side and at each end of the walking beam are attached the inboard crawlers 120 on their respective bogey mounts 116. The arrangement of the tractor units 120 on the outboard side and the inboard tractor units 120 in relation to the box frame 32 is essentially rectilinear (as shown in FIG. 6) with the inner ends of the tractors on each side in close relationship providing only enough space 130 to clear during steering. The wheel base and distance between the tractors across the machine can be varied to accommodate different sizes and weights of machinery. The bogey mountings on all four tractors pivot or turn on a vertical axis. This axis is coincident with the telescoping members on the inboard side and located at each end of the walking beam 124 on the outboard side and represented by the vertical pintle pin mountings 132.

The tractors each have individual hydraulic drive motors, i.e., the motors 134 (FIG. 3) for the inboard side and the motors 138 for the outboard side. These are two-way or reversible hydraulic motors such as Charlyn Orbit motors. The motors on each side are connected in series to each other by hydraulic hose lines (not shown) so as to operate in unison.

Each bogey mount 116 is attached to its respective crawler tractors by means of a cross-pin 146 (FIGS. 1,3 and d) and the bogey or saddle mounts clear the tops of the tractors sufiiciently to allow freedom of movement of these parts. In this manner the crawlers can negotiate obstacles such as unevennesses in the grade 50 and even large stones or culvert heads and the like that may be in the path of travel. Also each bogey mount 116 is pivoted on a vertical axis with the respective journal mountings 132 within or as part of these base members. The front pair of crawlers (FIG. 1) is tied together, fore and aft of the cross pin 146, by means of the paired tie bars 150 and 152. Similarly, the rear pair of crawlers is tied together by the tiebars 156 only one of which is shown. Each tie bar is constructed as an A-frame for rigidity and is mounted to an extension of the bogey mounts 116 by the pivot pins 160. By this arrangement the two fore and aft crawlers turn in a horizontal plane in unison. Steering of the front pair of crawlers is controlled by the double-acting hydraulic steering unit 162 (FIG. 1) having suitable pivot pins at each end on the outboard base 104 and on the tie bar 150. The hydraulic control hoses for the steering unit 162 are not shown. Similarly, steering for the rear pair of crawler units 120 is provided by the hydraulic steering unit 172 (FIG. 3) through a pivot pin on the base 104 and the pivot 176 on the tie bar 156..The hydraulic control hoses (not shown) supply the necessary hydraulic fluid to this steering unit.

As described in said parent application, the pair of front and rear adjustable suspensions 70 and 74, with their internal rams, are separately controlled to raise and lower the respective corners of the outboard side of the frame by pivoting the frame on the inboard pivot pin 128 carried by the walking beam to control the grade of the working tool. The dual suspensions 74 and 76 operate in unison central of the walking beam to control the slope of the working tool.

From the description thus far, it is seen that five adjustable mounts are included in the suspension, two being on the outboard side and three on the inboard side with means to control the level, direction and horizontal motion of the system. The machine travels on a construction site to carry the tool 30 along the prepared grade 50 under the guidance of the string line 182 (FIG. 1), which is supported from the horizontal arms 184 mounted on the adjustable brackets 186 from the string line posts 188'. The brackets 186 are adapted to be adjustable in height upon the posts 183 and also to vary the effective length of the horizontal arms 184. The string line 182 is placed outside of the edge of the grade 50 at any predetermined elevation above the grade and held by a plurality of spaced arms 184 therealong in a manner known in the art. The string line 182 is taut so as to represent the desired level and direction of the curbing 52 to be laid along the edge of the grade 50. The terrain from which the supports 188 extend need not be a finished grade as long as there is clearance around the string to allow passage of the sensors and the string 182 can be laid out in any desired curvature.

The machine is accurately guided along the string line 182 by means to detect the direction of the line and by means to detect the elevation of the line. The former variable is detected by the steering sensor 190, for the forward crawlers, and the steering sensor 190' for the rear crawlers. The latter variable is detected by the ele' vation sensors 192 and 192 which are mounted for passage along the string line directly behind and directly ahead of the steering sensors respectively. The steering sensors each have a vertical fork 194, the tines of which straddle the string line 182, while the elevation sensors have the horizontal forks 196 also straddling the string line. Both the elevation and steering sensors can be bar members held against the string line by biasing means with the elevation sensors riding under the line and the steering sensors riding along the inside of the line as is well known in the art.

The details of the adjustable mounting means for the sensors 190 and 190' are shown and described in said parent application and do not form a part of this invention. Each is slidably mounted, and fore and aft adjustment as well as angular adjustment is provided.

Cable means connected to radial arms, that turn with the tractors, move the steering sensor normal to the direction of steer are provided and are not further described except to point out that these means carry the sensor 190 back and forth in the same direction, or outwardly perpendicular to the line of travel when the crawler turns to the left (as viewed in FIG. 1) and inwardly perpendicular to the line of travel when the crawler turns to the right. Thus, as the fork 194 follows the string line, it is moved in a direction the same as the steering direction and perpendicular to the line of travel an amount proportioned by the ratio of the length of the radial control brackets to the effective change in direction imparted to the crawlers or an increment of that length.

As the machine follows the string line 182, the fork 194 momentarily strikes, is raised by, and passes over the horizontal supports 184 which are spaced along the string line. A limit switch (not shown), normally closed, is provided on the steering sensors 190, with a sensing spring 204 and a pendent arm, extending into operable relationship with the horizontal supports. The sensing spring on striking a support 184 momentarily opens the switch and breaks the circuit to the steering system.

The known manner of mounting the elevation sensors 192 and 192' is used such that when the elevation sensor strikes a horizontal support 184 for the string line 182, or which is too large to pass through its slot 196, the elevation sensor is moved about a pivot. This momentarily disconnects the sensor from the circuit by the movement of an actuator arm under the bias of an internal spring in a limit switch 206. After the elevation sensor passes the arm 184 it returns to its normal position in registry with the string line 182.

In operating a machine of this size and weight with accurate control while maintaining balance under a changing load of concrete, it was found that additional motive power was necessary to augment the pumps for the drive motors in order to adequately provide positive additional speed of travel of one side or the other of the machine to properly negotiate turns with the slipform in tangential or chordal relationship to the string line and at the same time maintain equilibrium control of the motive means. Experience indicated that this was true of the front of the machine where most of the weight may be and on the side where the curbing to be laid had a sharper than usual curvature. This additional integrated power and speed is provided by the suitable pumps which are used to cause the curve line of the tractors to take a path intermediate between the normal path and the actual curb line. By these means, both the machine and the slip-form are caused to pivot about their geometric centers 208 and 210 between the four tractors and over-steer sufficiently to lay the curb along the line called for by the guide line 182, that is, in the parallel, tangential or chordal relationship.

Under normal conditions the regular pumps supply the required hydraulic power for the motion of the machine through the tractor motors on the front crawlers and motors 134 and 138 for the rear crawlers with the control valves open and with both direction valves set for forward direction. Where additional power to one or both pairs of tractors is required, excess hydraulic pressure is delivered to either of the lines leading to these motors to increase the speed of operation of the desired outboard or inboard tractors to augment the steering system. As the tractors turn more power is supplied to the outside pair and less power is supplied to the inside pair.

The hydraulic system for the steering and leveling control of the machine need not be described. Flow of hydraulic fluid through the system is manifolded and is in both directions and returns to a sump in a manner known in this art. Safety relief valves, an accumulator and pressure gauges, are connected to the system in a known manner. A fan cooled radiator 208 (FIG. 4) can also be included to control the temperature of the hydraulic oil. The manifold and flow control valves for the system are indicated at 210 in FIG. 2, and includes a series of six double solenoid valves; for rear and front steering control, and solenoid valves for inboard level control and for outboard level control. Between each solenoid valve and the hydraulic part, controlled thereby, is a check valve and a flow control and shutoff valve.

The receiving hopper 12 is pivotally mounted from the frame 32 by means of a suitable bracket thereunder engaging the pivot pin 260 (FIG. 1). The receiving hopper 12 and the conveyor 18 with its helical screw (not illustrated) are unified and pivot together on the pin 260. The bracket 261, also supported rigidly by the frame 32, extends under the conveyor 18 to hold the assembly in the normal position shown in H6. 1 so that the discharge opening 22 is over the compaction hopper 24. During operation there is no tendency for the conveyor or receiving hopper to pivot. The pivot 260 can be eliminated and these parts can be rigidly supported from the frame. The pivot 260 provides a means to raise the conveyor upwardly by a cable or the like to an out of the way position during transport on a trailer. During transport the slip form 30 is removed from the side of the machine.

It is apparent that although the main portion of the weight of the on-board formable material (concrete) is upon the front tractors and is distributed over the outboard front tractor, in the embodiment shown, the feed hopper and conveyor can be otherwise located in relation to the compaction hopper and the slip form. Not

all of the weight is on the front out-board tractor since the compaction and extrusion of the concrete through theslip form has an upward moment of force which is transformed to the in-board side. Forward mounting of the receiving hopper not only facilitates loading from a truck at either a frontal position or side position, it also allows the curb machine operator to observe this operation as he controls the conveyor and watches the level of concrete in the compaction hopper.

The accuracy of the finished curb or surface laid by the device of this invention is not limited to preparation of a smooth preformed surface on which the tractors travel. During actual tests attempts were made to cause discrepancies in the end product 52 by large objects in the path of one or the other of the tractor units which cause the tractors to negotiate heights of or more. It was found that the machine leveled itself instantaneously and the conformation, level and direction of the product 52 was not disturbed. Mud holes and soft terrain are similarly negotiated.

The most efficient leveling was found to occur with the front and rear elevation sensors 192 located about opposite the levelers 70 and 72 on the outboard side although good level control is had with the sensors at any point ahead of and behind the pivot point 128 of the walking beam 124 and within its length. Placement of the elevation sensors 192 too far ahead or behind the unit disrupts the relationship between the string line and the immediate product being laid on the surface 50.

Similarly, some latitude is applied in the placement of the first and rear steering sensors. Best results are obtained with the front steering sensor 190 at or near the pivot point of the front wheel means or tractors and with the rear steering sensor at or near the discharge end of the slip-form. The key to these placements is the pivot point 128 of the walking beam, i.e., the sensors, whether elevation or steering, are placed fore and aft of the intersecting a line drawn through this pivot point normal to the line of travel when the steering units are at their midpoint. All tolerances can be kept within 0.01 inch and within the private and public specifications for road, curb, sidewalk and other construction work.

The machine is initially brought up to a position parallel to the grade line which is placed in relation to the grade upon which the curbing is to be laid such that the extensible members are at about their mid-points to allow maximum deviations of the rough grade under the tractors to be negotiated. The sensors are then located in relation to the grade line and the level of the machine is established manually. Any of the known types of grade control means can be used. The transverse slope control used for the inboard extensible members can be any proportional slope controller known in the art such as the type W 894 A supplied by Minneapolis Honeywell Co. with the type Q 625 A remote set unit which allows the operator to change the slope set point without leaving his position.

Referring to FIGS. 1 and 5, the general transverse relationship of the material handling system of this invention is shown and illustrated diagrammatically in relation to the tractors 120, the frame 32, the inboard suspension (dual contiguous sleeve members 74-76), the walking beam 124 and the outboard suspension 7072. It is seen that weight of the supply hopper l2 and the conveyor 18 is borne upon the pivot pin 260 on about the outboard side of the center line of the frame 32 with the fixed bracket 261 maintaining the angular relationship of these parts.

The axis of the conveyor 18 is at an angle to the vertical axis of the hopper so that the concrete is raised upwardly therefrom. During operation, the volume of the concrete in the hopper can vary from full capacity to 1.5 cubic yards, for example, to an empty condition. The capacity of the conveyor is about 0.5 cubic yards. Although the transverse shifting of the weight load on the pin 260 is gradual during the operation of the conveyor with no concrete being added from a truck, as soon as a new truck load of ready-mix arrives, the hoppet is filled to capacity in a matter of seconds and substantially rapid load shift to the suspension 74 occurs. Then asthe laying of curb progresses, the feed rate from the truck is coordinated with the rate withdrawal by the conveyor 18 so that the weight of concrete in both the hopper and conveyor remain substantially constant. During the interval when the empty truck is pulled away and a new truck load is brought into position, the curb laying continues and the weight of concrete in the hopper gradually diminishes, causing another load shift upon the suspension.

The compaction hopper 24 and the mule shoe 30 contains a substantial quantity of concrete (about 1.0 to 1.5 cubic yards) the supply of which is controlled by the conveyor 18 which is capable of intermittent operation by the operator of the machine. The hopper 24 and the mule shoe 30 are totally supported by the machine, that is the mule shoe does not normally contact the grade 50. However, there is a considerable upward moment of force caused by the compaction of the concrete in the hopper 24 and its extrusion through the mule shoe. Consequently, the level of concrete in the hopper 24, indicated at 262 is maintained at a substantially constant height above the grade 50 upon which the curb is being laid. This force tends to lift the frame from the inboard tractors 120 on the suspension -72 and its locus is generally forward of the pivot pin 128 (FIG. 4) of the walking beam which represents essentially the transverse center of the machine. However, the mule shoe is afi'txed longitudinally of the side of the frame (FIG. 6) and the effect of the upward force of the compaction is transmitted to both the front suspension unit 70 and the rear suspension unit 72. The vibrator 26 accentuates the compaction force and the extruded product 52 (FIG. 1) actually expands slightly from inside of the mule shoe as it is released at the rear end thereof.

Accordingly, the weight supported by the inboard and outboard pairs of tractors is constantly shifting in erratic cycles as the curb-forming process continues, but is constantly offset and balanced by the leveling system. The influence of soft grade, stones, obstacles and other deviations upon the tracks constitute additional factors that are compensated for by the leveling system.

In FIG. 6, a plan view of the machine, in schematic form, is shown in relation to the concrete handling system with geometric center of the slip-form shown at 210 and the geometric center of the suspension and tractors illustrated at 208. As the machine proceeds along the path of the arrow 54 under power to all four tractors, beside the grade and directional reference 182 and the curve is sensed, the front pair of tractors begin to turn in the direction of arrow 264 and follow the reference. At this time, the rear of the machine becomes a pivot point and the rear of the slip-form may be drawn away from the grade reference or toward the grade reference depending on the attitude of the rear tractors except for the control of the rear steering sensor which offsets this tendency by steering either away from or toward the reference by turning in the direction of arrows 266 or 267 under the control of the rear steering sensor. As the machine enters the curve less power is supplied to the inboard tractors and the outboard tractors begin to speed up. This action places the center 210 of the slip-form at a compromise position between the front and rear of the slip-form in relation to the reference. The slip-form moves tangentially to the curve of the string line 182. As the front tractors begin to follow the curve of the reference the center 208 is moved toward the reference and again this action is offset by the rear steering sensor and tractors by turning further in the direction of the arrow 266. The tangential relationship of the slip-form 30 to the reference 182 is preserved.

It is apparent that with the receiving hopper located on one side and frontal ofthe machine and the compaction hopper on the other side, with the conveyor in between, full advantage of the suspension, traction and steering capabilities of the machine can be realized so that only that portion of the grade upon which the formable material is being laid need be leveled or finished to any substantial degree or to meet local or state specifications if a roadway is contemplated. Also, the longitudinal side location of the working tool in cooperation with the steerable fore and aft pairs of ground engaging means maintains the tool in a tangential relationship to outside curves and in a chordal relationship to inside curves whereby maximum conforming accuracy of finished curb to grade reference is not upset by deviations in the grade or changes in the center of gravity of the onboard supply of formable material, such as concrete. The hopper 12 can be located forward of the position shown in FIG. 6 with the conveyor 18 placed at an angle therefrom in front of the suspension 70 to the compaction hopper 24. The combination of the compaction hopper and side-mounted slip-form can be used without the receiving hopper on smaller two-track machines to an advantage where accuracy of curve manipulation or negotiation of an uneven grade are not critical to the job to be accomplished.

What is claimed is:

I. In a construction machine for the controlled distribution of concrete through a slip-form along a graded ground surface, the combination of:

a main frame;

independently adjustable vertical extensible mem bers carried by and spaced fore and aft along one side of said main frame;

a single independently adjustable vertical extensible member carried substantially central of the other side of said main frame;

a walking beam disposed along said other side of said main frame and pivotally mounted on a horizontal transverse axis from said single extensible member;

a self-propelled fore and aft tractor unit pivotally mounted on a vertical axis from said walking beam and spaced from said horizontal transverse axis thereof;

the pair of fore mounted tractor units being crosslinked to steer in unison about their respective vertical axes and the pair of aft mounted tractor units being cross-linked to steer in unison about their respective vertical axes; drive means connected to said tractor units and adapted to simultaneously drive the fore and aft tractor units on either side of said main frame in unison; actuating means supported by said main frame and operatively connected to the extensible members on said one side of said main frame responsive to an exterior grade control reference disposed along said ground surface to control the grade of said main frame; actuating means supported by said main frame and operatively connected to said single extensible member on the other side of said main frame to control the transverse slope of said main frame; an open-topped receiving hopper carried by said main frame and disposed for access from a side of said main frame; an open-topped compaction hopper carried by said main frame and disposed from a side opposite that of said receiving hopper, the open top of said compaction hopper being above the open top of said receiving hopper; conveyor means carried by said main frame at an angle between the bottom of said receiving hopper with its discharge end over the open top of said compaction hopper; an elongated slip-form supported by said main frame and disposed along a side thereof; said slip-form having an open bottom adjacent to said graded ground surface with the fore end thereof in communication with said compaction hopper; and the longitudinal axis of said slip-form being disposed contiguous to the tractor units on thatside of the main frame whereby in turning said pairs of tractors to negotiate a curve defined by said exterior grade reference the longitudinal axis of said slipform is maintained substantially tangential to an outside curve and substantially chordal to an inside curve. 2. A construction machine in accordance with claim in which: said receiving hopper and said conveyor means are unified; said compaction hopper and said slip-form are unified; said receiving hopper and conveyor means are pivotaliy supported by said main frame transversely thereof; the longitudinal axis of said slip-form extends substantially parallel with the pivot axis of said unified receiving hopper and conveyor; and adjustable means are provided supporting said unitized compaction hopper and slip-form from said side of said main frame. 3. A construction machine in accordance with claim in which: drive means for actuating said conveyor are provided to carry formable material upwardly from said receiving hopper to said discharge end into said compaction hopper; and means are provided to control the rate of discharge of said conveyor means whereby the level of formable material in said compaction hopper is maintained substantially constant.

e :i: t: a: 

1. In a construction machine for the controlled distribution of concrete through a slip-form along a graded ground surface, the combination of: a main frame; independently adjustable vertical extensible members carried by and spaced fore and aft along one side of said main frame; a single independently adjustable vertical extensible member carried substantially central of the other side of said main frame; a walking beam disposed along said other side of said main frame and piVotally mounted on a horizontal transverse axis from said single extensible member; a self-propelled fore and aft tractor unit pivotally mounted on a vertical axis from said walking beam and spaced from said horizontal transverse axis thereof; the pair of fore mounted tractor units being cross-linked to steer in unison about their respective vertical axes and the pair of aft mounted tractor units being cross-linked to steer in unison about their respective vertical axes; drive means connected to said tractor units and adapted to simultaneously drive the fore and aft tractor units on either side of said main frame in unison; actuating means supported by said main frame and operatively connected to the extensible members on said one side of said main frame responsive to an exterior grade control reference disposed along said ground surface to control the grade of said main frame; actuating means supported by said main frame and operatively connected to said single extensible member on the other side of said main frame to control the transverse slope of said main frame; an open-topped receiving hopper carried by said main frame and disposed for access from a side of said main frame; an open-topped compaction hopper carried by said main frame and disposed from a side opposite that of said receiving hopper, the open top of said compaction hopper being above the open top of said receiving hopper; conveyor means carried by said main frame at an angle between the bottom of said receiving hopper with its discharge end over the open top of said compaction hopper; an elongated slip-form supported by said main frame and disposed along a side thereof; said slip-form having an open bottom adjacent to said graded ground surface with the fore end thereof in communication with said compaction hopper; and the longitudinal axis of said slip-form being disposed contiguous to the tractor units on that side of the main frame whereby in turning said pairs of tractors to negotiate a curve defined by said exterior grade reference the longitudinal axis of said slip-form is maintained substantially tangential to an outside curve and substantially chordal to an inside curve.
 2. A construction machine in accordance with claim 1 in which: said receiving hopper and said conveyor means are unified; said compaction hopper and said slip-form are unified; said receiving hopper and conveyor means are pivotally supported by said main frame transversely thereof; the longitudinal axis of said slip-form extends substantially parallel with the pivot axis of said unified receiving hopper and conveyor; and adjustable means are provided supporting said unitized compaction hopper and slip-form from said side of said main frame.
 3. A construction machine in accordance with claim 1 in which: drive means for actuating said conveyor are provided to carry formable material upwardly from said receiving hopper to said discharge end into said compaction hopper; and means are provided to control the rate of discharge of said conveyor means whereby the level of formable material in said compaction hopper is maintained substantially constant. 